And so I get around to checking out the Yandere no Onna no Ko website
And it turns out that in the third volume, there’s a yandere robot maid (a ‘maidroid’).
Say hello to Yumia.
I think the backstory for her track is the onii-chan in this CD found her in the trash. He takes her home, and when he switches her on, he finds she has no memory of how she got there, or who her master is. And thus the onii-chan gains a robot maid.